
The languages \(\lbrace  w \in \lbrace 0,1\rbrace ^* \mid |w|_0 \le |w|_1 \rbrace \)  and \(\lbrace  w \in \lbrace 0,1\rbrace ^* \mid |w|_0 = |w|_1 \rbrace \) , where \(|w|_a\)  denotes
the number of occurrences of \(a\)  in \(w\) , see e.g. [1]}.

The computation (of a certain bit) of the binary representation of the product of two (or any number of)
binary encoded integers [2]}.

The computation (of a certain bit) of the binary representation of the integer quotient of two binary encoded integers [2]}.

The word problem for every infinite solvable linear group [4]}.

The conjugacy problem for the Baumslag-Solitar group \(\mathsf {BS}(1,2)\)  [5]}.

